Sleeves of this type are currently used for loading a transportable container, for example mounted on a lorry, truck, or possibly ships or barges.
The sleeves of this type are generally constituted by a tubular structure of supple material provided at regular intervals with reinforcing elements in the form of stepped hoops or rings or helically disposed turns.
These devices allow an unused part of the sleeve to be retracted in accordeon-like manner in order to clear the free space beneath the silo or the loading assembly in particular to allow the carrying vehicle to arrive and depart.
The sleeve is conventionally raised by a traction exerted from an upper winch on cables or ropes supporting by their lower ends a discharging cone at which the end of the sleeve terminates.
In the most frequent case of the sleeve not being totally in position of extension, a part thereof, contracted or folded in accordeon form, consequently remains at the base of the sleeve.
This part, retracted in the manner of an accordeon, reduces the diameter of passage of the sleeve with respect to the stretched part, with the result that the pulverulent or granular materials which finish their fall with a considerable force of percussion, strike against this retracted part, causing rapid wear and tear due to the abrasive action of the materials.
It is a first object of the invention to provide a sleeve of which the active part, serving for transit of the products from the base of the hopper or silo towards the receiving container, is in stretched position without retracted fold, consequently offering a relatively smooth surface when the bulk materials drop, and avoiding sources of abrasion.
A further object of the invention is to avoid the formation at the base of the sleeve, in the retracted part, of pockets in which the products might accumulate.